Vertical reciprocating conveyors are employed by warehouses, factories, and the like to convey materials between different vertical levels. The typical vertical conveyor includes a supporting structure or frame and a carriage, which is adapted to support a cargo or load, is guided for vertical movement on the supporting structure. The carriage can be moved upwardly and downwardly on the structure by either a mechanical or hydraulic drive. In one common form of vertical conveyor, the carriage or platform is lifted and lowered by drive chains that are located on opposite sides of the carriage. Each drive chain passes over a drive sprocket that is joined to the drive shaft on opposite ends of the drive shaft. The drive shaft is rotated by a drive motor and lifting and lowering is accomplished through operation of the drive motor.